The impact of pelvicalyceal anatomy on the stone formation in patients with lower pole renal stones

Abstract

Background: The aim of our study was to determine whether various anatomic factors constitute a predisposition to a lower pole renal stones. Materials and methods: We analysed the computed tomography (CT) urography of 75 patients with a single lower pole stone. Measurements were taken of the infundibulopelvic angle (IPA), infundibular width (IW), infundibular length (IL) and calyceopelvic height (CPH). Results: The mean patient age was 50 years (range 17-79 years). The mean stone size was 11.9 mm. The mean IPA using Sampaio method in affected kidney was 113.4 ± 15.3o (range 80-139o), 59.5 ± 17.3o using Elbahnasy method. The values of IPA on the contralateral kidney were 119.86 ± 15.37o (range 79-141o; p = = 0.001) using Sampaio method of measurement and 59.78 ± 12o (range 34-90o; p = 0.465) using the method described by Elbahnasy. We reported statistically significant differences between stone-bearing kidney and contralateral kidney in measurement IPA using only Sampaio method. The mean infundibular width was 4.22 ± 1.81 mm on the affected kidney and 3.72 ± 2.5 mm on the contralateral side (p = 0.164). The mean infundibular length was 15.37 ± 4.57 mm on the affected kidney and 14.66 ± 4.35 mm on the unaffected side (p = 0.329). The CPH was 10.19 ± 4.05 mm on the affected kidney and 10.44 ± 3.83 mm on the normal side (p = 0.688). Conclusions: Pelvicalyceal morphology of the kidney is one of the factors that determine the risk of developing kidney stones. Out of the analysed morphological parameters of kidney IPA is a statistically significant risk factor to form lower pole kidney stones. Other anatomic parameters did not seem to have a significant role in predisposing to form lower pole kidney stone.